Reviewers are usually people who would have been, poets, historians, biographer, if they could. They have tried their talents at one thing or another and have failed; therefore they turn critic.
There is a difference between responsible criticism that aims for success and defeatism that refuses to acknowledge anything but failure. Hindsight alone is not wisdom, and second-guessing is not a strategy.
An artist must only judge of what he understands, his field is just as limited as that of any other specialist... That in his sphere there are no questions, but only answers, can only be maintained by those who have never written and have had no experience of thinking in images.